Embodiments described herein relate generally to methods and apparatus for determining a network topology, for example, during network provisioning. Some embodiments relate more specifically to providing centralized topology management of computing resources including virtual resources within a data center that is accessible to external management entities.
Server management tools typically manage and provision computing resources within networks, data centers, and enterprises. For example, network management tools can manage and provision network devices and network resources in a network. Similarly, server management tools can be used to launch applications, manage instantiation and migration of virtual machines, and balance processing loads on servers and/or other computing resources. Network management tools can be used to start and stop network services provided by network devices and set access policies within a network.
Known server management tools and network management tools typically rely on a static description of the network in which the managed resources exist that is provided by a network administrator of the network. For example, a server management tool used to manage servers and/or virtual machines within a network might rely on, for example, an internet protocol (“IP”) address for each server or virtual machine being managed that is provided by a network administrator to communicate with the servers in the network. Alternatively, a resource running on a server in the network can dynamically transmit or broadcast the IP address of the server on which it is running. The server management tool can receive and store the broadcast IP address to communicate with that server.
Similarly, known network management tools typically require that a network administrator provide a static description of the topology of the network to a network management tool. Such a static description can include textual and/or other files that describe where (e.g., on which server in the network) particular virtual machines or virtual resources are instantiated. Additionally, a static description can describe the interconnections among network devices such as routers, hubs, switches, and gateways, and the interconnection between these network devices and servers or virtual machines in the network. These network management tools can interpret such a description to apply, for example, an access control list (“ACL”) for a particular virtual machine to the port of a network device to which the virtual machine is connected. Alternatively, network devices can be queried dynamically for information about the interconnections of the network devices. For example, the simple network management protocol (“SNMP”) provides for some querying and gathering of information from network devices.
Such known methods of server and network management suffer several disadvantages. For example, static descriptions of network topology (including binding of virtual resources to network devices) are problematic in virtualized networks such as data center networks. In a virtualized network, multiple virtual resources such as virtual machines run on a single physical server. Typically in virtualized networks, virtual machines can migrate or move from one server to another within the network, changing dynamically the binding of virtual resources to network devices within the network. Thus, static descriptions of the network quickly become outdated (e.g., inaccurate or incorrect). When the static description of a network is no longer valid due to, for example, migration of a virtual resource, a network administer typically updates the static description of the network in order to provision network devices to manage the network based on the new topology to further manage the network.